/*
 * Copyright (c) 1997, 2018 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0, which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 *
 * This Source Code may also be made available under the following Secondary
 * Licenses when the conditions for such availability set forth in the
 * Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
 * version 2 with the GNU Classpath Exception, which is available at
 * https://www.gnu.org/software/classpath/license.html.
 *
 * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
 */

package javax.faces.lifecycle;

import java.util.Iterator;

import javax.faces.FacesWrapper;


/**
 * <p><strong class="changed_modified_2_0 changed_modified_2_3">LifecycleFactory</strong> is
 * a factory object that creates (if needed) and returns {@link
 * Lifecycle} instances.  Implementations of JavaServer Faces must
 * provide at least a default implementation of {@link Lifecycle}.
 * Advanced implementations (or external third party libraries) MAY
 * provide additional {@link Lifecycle} implementations (keyed by
 * lifecycle identifiers) for performing different types of request
 * processing on a per-request basis.</p>
 *
 * <p>There must be one <code>LifecycleFactory</code> instance per web
 * application that is utilizing JavaServer Faces.  This instance can be
 * acquired, in a portable manner, by calling:</p>
 * <pre>
 *   LifecycleFactory factory = (LifecycleFactory)
 *    FactoryFinder.getFactory(FactoryFinder.LIFECYCLE_FACTORY);
 * </pre>
 *
 * <p class="changed_added_2_3">Usage: extend this class and push the implementation being wrapped to the
 * constructor and use {@link #getWrapped} to access the instance being wrapped.</p>
 */

public abstract class LifecycleFactory implements FacesWrapper<LifecycleFactory> {

    private LifecycleFactory wrapped;

    /**
     * @deprecated Use the other constructor taking the implementation being wrapped.
     */
    @Deprecated
    public LifecycleFactory() {

    }

    /**
     * <p class="changed_added_2_3">If this factory has been decorated,
     * the implementation doing the decorating should push the implementation being wrapped to this constructor.
     * The {@link #getWrapped()} will then return the implementation being wrapped.</p>
     *
     * @param wrapped The implementation being wrapped.
     */
    public LifecycleFactory(LifecycleFactory wrapped) {
        this.wrapped = wrapped;
    }

    /**
     * <p class="changed_modified_2_3">If this factory has been decorated, the
     * implementation doing the decorating may override this method to provide
     * access to the implementation being wrapped.</p>
     *
     * @since 2.0
     */
    @Override
    public LifecycleFactory getWrapped() {
        return wrapped;
    }


    /**
     * <p>The lifecycle identifier for the default {@link Lifecycle} instance
     * for this JavaServer Faces implementation.</p>
     */
    public static final String DEFAULT_LIFECYCLE = "DEFAULT";


    /**
     * <p>Register a new {@link Lifecycle} instance, associated with
     * the specified <code>lifecycleId</code>, to be supported by this
     * <code>LifecycleFactory</code>.  This method may be called at
     * any time, and makes the corresponding {@link Lifecycle} instance
     * available throughout the remaining lifetime of this web application.
     * </p>
     *
     * @param lifecycleId Identifier of the new {@link Lifecycle}
     * @param lifecycle {@link Lifecycle} instance that we are registering
     *
     * @throws IllegalArgumentException if a {@link Lifecycle} with the
     *  specified <code>lifecycleId</code> has already been registered
     * @throws NullPointerException if <code>lifecycleId</code>
     *  or <code>lifecycle</code> is <code>null</code>
     */
    public abstract void addLifecycle(String lifecycleId,
                                      Lifecycle lifecycle);


    /**
     * <p>Create (if needed) and return a {@link Lifecycle} instance
     * for the specified lifecycle identifier.  The set of available
     * lifecycle identifiers is available via the
     * <code>getLifecycleIds()</code> method.</p>
     *
     * <p>Each call to <code>getLifecycle()</code> for the same
     * <code>lifecycleId</code>, from within the same web application,
     * must return the same {@link Lifecycle} instance.</p>
     *
     * @param lifecycleId Lifecycle identifier of the requested
     *  {@link Lifecycle} instance
     *
     * @throws IllegalArgumentException if no {@link Lifecycle} instance
     *  can be returned for the specified identifier
     * @throws NullPointerException if <code>lifecycleId</code>
     *  is <code>null</code>
     *
     * @return the {@code Lifecycle} instance
     */
    public abstract Lifecycle getLifecycle(String lifecycleId);


    /**
     * <p>Return an <code>Iterator</code> over the set of lifecycle
     * identifiers supported by this factory.  This set must include
     * the value specified by <code>LifecycleFactory.DEFAULT_LIFECYCLE</code>.
     * </p>
     *
     * @return an {@code Iterator} over the set of lifecycle
     * identifiers supported by this factory
     */
    public abstract Iterator<String> getLifecycleIds();


}
